Monday, January 10, 2011

Theory Update 34

Today's view of triality is the $21$ edges of our favourite polytope: the Stasheff associahedron in three dimensions! At each trivalent vertex there is a triplet $(A,B,C)$ of edges. The vertex signs are then defined by the cycling of the letters at the vertex. An arbitrary source and target vertex are marked.

1. OK, so I believe I counted $21 = 3 \times 7$ correctly, but please check the invariance of letter permutations ...